Antibiotic susceptibility testing of bacteria is performed by culturing a sample container containing bacteria and an antibacterial agent under an environment adjusted to a temperature suitable for proliferation of bacteria and by measuring the degree of proliferation using absorbency, turbidity, and the like. Currently, an inspection is performed on the proliferation of bacteria by turbidity measurement, visual observation, or optical measurement of absorbency after overnight culture.
To determine the degree of proliferation of bacteria, by performing the culture for a long time at a temperature suitable for the proliferation of bacteria, the degree of proliferation of bacteria is determined by sufficiently differentiating the state of proliferation. In United States Clinical and Laboratory Standards Institute (CLSI), culture conditions at this time are defined as 35° C.±2° C. Here, in the susceptibility inspection, since the determination is made based on whether or not the variation in proliferation due to the temperature difference of a culture solution exceeds the prescribed turbidity after culturing for a long time, the temperature variation of about ±2° C. is not matter.
The long culture time of whole day and night and the subsequent inspection process will result in delayed dosing and a heavy burden on the patient. Therefore, shortening of the inspection is desired for rapid treatment. In order to determine the proliferation of bacteria in a short time, it is important to manage the culture solution of each well in the sample container at a uniform temperature, and set the same culture conditions among the wells as much as possible.
Usually, in a sample container having a plurality of wells, the culture is performed using an incubator (constant temperature bath). However, in the conventional device, it is not possible to perform an optical measurement by disposing an image pickup apparatus inside the incubator. Further, there is a device that heats a sample container with an incubator and conveys the sample container to a measuring unit at the time of turbidity measurement (PTL 1). However, in such a device, there is a problem that the temperature of the sample container decreases while an image is picked up using the image pickup apparatus.
Since the turbidity measurement can be performed in a relatively short time, the temperature drop during measurement can be ignored. However, it takes a long time to perform the image pickup with the image pickup apparatus, and the temperature of the sample container decreases during image pickup of all the wells, which causes variations in subsequent proliferation. For this reason, it is difficult to obtain an accurate determination result.
Meanwhile, there is a device that heats the sample container using a heating device (a heat plate) directly under the measuring device (PTL 2). In the case of this device, it is difficult to equalize the temperature of the culture solution in each well of the sample container. Generally, the reason is that heat is easy to escape at the end portion of the heat plate, and the temperature drops. Even in this case, variations will occur in the subsequent amount of the proliferation of bacteria, making it difficult to obtain an accurate determination result.